elemental-register: rsync logging (rather) useless

[kkaempf]

I see that rsync gets called with --human-readable but the actual output doesn't reach the logs.

There is a (repeated) Syncing data... output but that's rather useless for actual progress.

Sep 22 12:54:13 rancher-26321 elemental-register[16531]: DEBU[2023-09-22T12:54:13Z] Running cmd: 'rsync --progress --partial --human-readable --archive --xattrs --acls --exclude=/mnt --exclude=/proc --exclude=/sys --exclude=/dev --exclude=/tmp --exclude=/host --exclude=/run /run/rootfsbase/ /run/cos/workingtree/'
Sep 22 12:54:13 rancher-26321 systemd[1]: run-rcf4160568d4a470f98fe052f81ed5ca6.scope: Deactivated successfully.
Sep 22 12:54:18 rancher-26321 elemental-register[16531]: DEBU[2023-09-22T12:54:18Z] Syncing data...
Sep 22 12:54:23 rancher-26321 elemental-register[16531]: DEBU[2023-09-22T12:54:23Z] Syncing data...
Sep 22 12:54:28 rancher-26321 elemental-register[16531]: DEBU[2023-09-22T12:54:28Z] Syncing data...
Sep 22 12:54:33 rancher-26321 elemental-register[16531]: DEBU[2023-09-22T12:54:33Z] Syncing data...
Sep 22 12:54:38 rancher-26321 elemental-register[16531]: DEBU[2023-09-22T12:54:38Z] Syncing data...
Sep 22 12:54:43 rancher-26321 elemental-register[16531]: DEBU[2023-09-22T12:54:43Z] Syncing data...

[davidcassany]

The story is around having some sort of feedback, to actually see the process is not stuck. IIRC in case of a rsync failure the logs of rsync are kept and included within elemental logs, that's why the --human-readable is there. We used to have weird race issues while trying to also stream the logs from rsync to elemental-logs (we were using an external library we dropped because of that) so we opted for a safe an simple approach. We can revisit it though and do an attempt of including some sort of progress data on each Syncing data....

In any case this can be slightly tricky and provide arguable value.

[kkaempf]

in case of a rsync failure the logs of rsync are kept

maybe simply adding one log line, saying where the logs are ?
Then people interested in details can switch from journalctl -f to tail -f <rsync-log-file> ?!

[fgiudici]

NOTE: issue transfered from elemental-operator to elemental-toolkit as the rsync call and logs come from the "install" call of the toolkit "elemental" binary.